Like many of you, I grew up in “healthcare” with the view that vitamin D toxicity is a significant concern for those taking supplements. Even today, individuals with nutrition degrees maintain the notion that vitamin D supplementation is a risky endeavor. Consider your own visceral response to the following:

“Many individuals would do well to take 10,000 IU’s of vitamin D for several months straight, perhaps longer.”

Such a statement can lead to very emotional responses, particularly in those who have been exposed to the infamous vitamin D cliché, i.e., that vitamin D toxicity due to excessive supplementation is a serious concern and has been deadly in the past. And published articles have advanced this notion.

In 1998, an article published in the New England Journal of Medicine contained the following statement: “excess vitamin D causes hypercalciuria (and hypercalcemia), but these complications do not occur unless the daily dose exceeds at least 2400 IU.”1 If this were true, there would be good reason to react to the suggestion that 10,000 IU’s of vitamin D is safe and reasonable for many individuals.

Dr. Reingold Vieth, a Canadian researcher, has cleared up this apparent confusion in a very concise commentary published in 2002.2 There are two forms of supplemental vitamin D; one is ergocalciferol (vitamin D2), and the other is cholecalciferol (vitamin D3). Vitamin D2 is not normally found in humans; and Vieth explains that all iatrogenic cases of vitamin D toxicity in the literature involved vitamin D2 supplementation. Poisonings have occurred with vitamin D3; however, these cases involved unintentional prolonged intake of greater than 40,000 IU’s. Consider the following statement made by Vieth regarding vitamin D intake: “Long-term use of 4000 IU’s of vitamin D3 per day is, in reality, a physiologic dose that has no effect on calcium levels in serum or urine.”2

This would not likely be surprising if we previously knew that, in just 15-20 minutes of full body sun exposure in the summertime, our skin generates about 10,000 IU’s of vitamin D3; longer sun exposure generates no more vitamin D.2 In fact, about 90% or more of our vitamin D should come from sun exposure. It is impossible to acquire adequate amounts of vitamin D from the diet; indeed, Paleolithic man consumed virtually no vitamin D.3 And now, in modern times, we have been scared out of the sun, for fear of developing skin cancer. Based on this information, it is likely that modern man suffers from a chronic deficiency of vitamin D.

Despite this information, it would not be surprising for readers to remain reticent about vitamin D supplementation; as mentioned earlier, we have all been strongly conditioned to fear and avoid vitamin D. For those with such concerns, there is a simple solution. A blood test for vitamin D is available; 25(OH)D is the recommended test. A recent paper by Dr. Bruce Hollis from the Medical University of South Carolina maintains that 25(OH)D levels below 80 nmol/L represents a state of vitamin D deficiency.4

Readers should think for a moment on the last condition listed above. Is it really possible that vitamin D is a cause of chronic musculoskeletal pain? If this were true, this connection might make us re-think how we view spine pain.

In 2002, Faraj and Mutairi reported, in the journal Spine, that chronic low back pain may be caused by vitamin D deficiency. A total of 360 subjects with idiopathic chronic low back pain for at least six months were included in this study. The researchers used 22.5-93.8 nmol/L of 25(OH)D as the normal range, which actually represents a deficient level when compared to the values outlined by Hollis4 and Vasquez, et al.5

Faraj and Mutairi determined that 299 subjects had vitamin D levels bellow 22.5 nmol/L, and 61 were within the “normal” range. All 360 subjects took vitamin D supplements for three months, at doses that will shock most readers. Those who weighed less than 110 pounds, took 5,000 IU’s vitamin D and those who weighed more than 110 pounds took 10,000 IU’s. Out of the 360 supplemented subjects, 341 reported a disappearance of their back pain, and there were no reported side-effects.5 The authors concluded that all patients with chronic low back pain should be screened for vitamin D deficiency.

How many of your patients with chronic pain are not responding to your care? Is it possible that they may be suffering from vitamin D deficiency? If you decide to supplement with vitamin D, make sure to supplement with cholecalciferol and not ergocalciferol.

Dr. Seaman is the Clinical Chiropractic Consultant for Anabolic Laboratories, one of the first supplement manufacturers to service the chiropractic profession. He is on the postgraduate faculties of several chiropractic colleges, providing nutrition seminars that focus on the needs of the chiropractic patient. He is also a faculty member at Palmer College of Chiropractic Florida, where he teaches nutrition and subluxation. He can be reached by e-mail at
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